Printing apparatus

ABSTRACT

A continuous printer including a framework supporting an endless platen and means to move material onto the platen for movement therewith. Printing means comprising an endless stencil screen mounted on spaced rolls are disposed adjacent to one run of the platen for printing the material and includes ink distributing means. The ink distributing means includes a housing removably supported on the framework and defining a substantially enclosed ink cavity disposed about an applicator roller journalled in the housing. A table supports the run of the platen opposite the printing means and a friction reducing band of a material of a lower surface friction coefficient than that of the material of the platen is disposed between the rungs of the platen and has a run which extends between the platen and the table and is movable with the platen for reducing friction between the platen and the table. Toothed means are provided for movement with the platen and mesh with toothed means on the screen supporting rollers to drive the rollers and to insure continued registration between the stencil screen and the material to be printed.

United States Patent [191 Vasilantone 1 1 PRINTING APPARATUS [76] Inventor: Michael Vasilantone, 147 E. First Ave., Roselle, NJ. 07203 [22] Filed: Jan. 4, 1973 121] Appl. No.: 321,016

[52] US. Cl 101/122, 101/126, 198/184, 226/171 [51] Int. Cl B411 13/08 [58] Field of Search 101/121, 122, 126, 232; 198/184; 226/171, 172; 271/45, 198

[56] References Cited UNITED STATES PATENTS 2,276,181 3/1942 Foster 101/122 2,774,462 12/1956 Poundstone 198/139 2.880.998 4/1959 Middleton 271/45 3,103,167 9/1963 Zeuthen 101/122 3,468,247 9/1969 Vasilantone 101/115 3,703,284 11/1972 Hesen 198/184 X 3,711,090 l/l973 Fielder 198/184 X Primary Examiner-Robert E. Pulfrey Assistant Examiner-R. E. Suter Attorney, Agent, or FirmEdward E. Dyson; John J. Byrne [57] ABSTRACT A continuous printer including a framework supporting an endless platen and means to move material onto the platen for movement therewith. Printing means comprising an endless stencil screen mounted on spaced rolls are disposed adjacent to one run of the platen for printing the material and includes ink distributing means. The ink distributing means includes a housing removably supported on the framework and defining a substantially enclosed ink cavity disposed about an applicator roller journalled in the housing. A

table supports the run of the platenopposite the printing means and a friction reducing band of a material of a lower surface friction coefficient than that of the material of the platen is disposed between the rungs of the platen and has a run which extends between the platen and the table and is movable with the platen for reducing friction between the platen and the table. Toothed means are provided for movement with the platen and mesh with toothed means on the screen supporting rollers to drive the rollers and to insure continued registration between the stencil screen and the material to be printed.

4 Claims, 6 Drawing Figures PATENIEUnnv 12 1914 SHEEF 0F 3 PRINTING APPARATUS This invention relates to a printing machine and more particularly to a printing machine for continuously printing a web of material of indeterminate length.

This invention is an improvement over the continuous printing machine disclosed in my U.S. Pat. No. 3,468,247, issued Sept. 23, 1969, entitled: CONTINU- OUS PRINTER WITH MEANS TO MAINTAIN A MOVING WEB LATERALLY TAUT. Generally, that patent discloses dual, vertically spaced endless platens with printing means disposed therebetween for printing on two oppositely moving flexible webs simultaneously, and is particularly directed toward means for laterally stretching the flexible material taut on its respective platen. Such means include-an endless locking strip on each side of each platen and movable therewith which strip stretches the material taut on the platen by clamping overlapping edge of the material against the vertical side edges of the respective platens.

In many prior art printing machines, not necessarily continuous printers of the type with which this application is concerned, using roller ink-applicators, the roller is substantially entirely exposed to the atmosphere such that the ink applied thereto tends to dry up and cake on the roller after a period of time. This problem has become magnified by the increasing use of inks which dry very rapidly upon exposure to the atmosphere. It is highly desirable to maintain these quickdrying inks free from exposure to the atmosphere until the last possible moment. Additionally, inks give off fumes or odors which are highly irritating to the eyes and the skin of close-by workers and are otherwise a dangerous source of pollution for the working atmosphere.

Another problem in prior art continuous stencil printing machine is the slippage or gradual loss of registration between the stencil screen of the printing means and the material to be printed. Generally, the rollers and stencil screen are driven by friction, both by the platen and, as in my above-mentioned patent, by the locking strip. In friction drive systems nothing is provided to positively maintain proper registration between the screen and the platen and consequently the material on the platen. This problem becomes particularly acute in situations where a plurality of stencil printing means are used for printing different portions of the same pattern on a particular run of material. Minute variations in sizes of the stencil supporting rollers, for example, are magnified after extended periods of time and the printing means will not be in complete registration with the previously printed portions of the material.

Another difficulty in continuous printers especially of the endless platen type is the friction encountered by the rubberlike heavy platen against its supporting table. Generally a supporting table must be employed on the underside of the platen opposite the printing station. The friction between the rather heavy belt and the table creates a substantial load on the drive means for v the platen. Additionally, guide rails are generally employed along the side edges of the platen increasing the frictional forces and thereby creating an additional load on the platen belt drive motor.

It is an object of this invention to overcome the above-mentioned problems in continuous stencil printing machines.

More specifically, it is an object of this invention to provide an ink distributing assembly which includesa housing surrounding an applicator roller which housing defines an enclosed ink cavity and which substantially protects the ink from exposure to the atmosphere until application to the stencil.

It is another object of this invention to provide means for recirculating the excess ink from the applicator roller during each revolution and after it has been momentarily exposed to the atmosphere. The recirculated ink is mixed with fresh ink within the cavity defined by the housing.

It is another object of this invention to assure proper registration of the rollers upon which the stencils are mounted by providing cooperating gear means between the moving platen and the stencil supporting rollers insuring registration between the print means and the platen and consequently the material to be printed.

It is another object of this invention to reduce the frictional forces between the platen and the supporting table by providing a friction reducing band having a surface friction coefficient considerably less than that of the platen material and being positioned between the platen and its supporting table and being movable with the platen. It is another object of this invention to use similar friction reducing bands to reduce friction along the side edges of the locking strips which engage and move with the platen.

It is a further object of this invention to provide a'roller having a particular surface configuration for a more uniform application of ink to the stencil. It is to be understood that in stencil printing the screen is flooded with ink prior to being imprinted by a squeegee. The squeegee actually does the printing while the applicator roller regulates the amount of ink feed to the flood area and recirculates the excess ink. More specifically, the applicator roller has a corrugated surface, the corrugations being in planes transverse to the longitudinal axis of the roller..The corrugated surface better retains the ink the roller picks up from the cavity, thereby insuring a more even distribution of ink. Adjustable doctor blades having edge configurations to mate with the corrugated surface are positioned about the roller. One doctor blade limits the amount of ink transferred by the roller to the stencil, while another removes excess ink from the roller after it contacts the stencil for remixing with fresh ink in the ink cavity.

More particularly this invention includes an apparatus for continuously printing insignia on a moving flexible material comprising a framework and a moving platen on the framework for receiving the material to be printed. Means are provided for moving the material onto the platen for movement with the platen. Locking strips run with the platen and clamp overlapping edges of the material against the vertical side of the platen. Stencil printing means are provided having one side adjacent to and movable with the flexible material on the platen and include an ink distributing assembly mounted on the framework adjacent to the other side of the stencil printing screen for forcing ink through the screen onto the material. The assembly includes a housing having a top and front and rear sides and being open at its bottom side adjacent to the other side of the stencil printing screen and extending across the screen. End plates are provided on the housing whereby the housing defines a substantially enclosed ink cavity about the applicator roller.

The roller applicator is journalled in the housing extending across the open side of the housing for rolling engagement with the stencil printing screen. Squeegee means are attached to the rear side of the housing and extend downwardly into contact with the screen.

In an embodiment of the invention, a second platen is provided and a second ink distributing assembly is provided for the second platen. The second platen is vertically spaced above the first platen and sandwiches the stencil printing means therebetween. Support tables support that portion of the platen runs which are opposite the printing means and endless friction reducing bands are provided within the confines of the end less platens, each having a run which extends between the supporting table and the platen for purposes of reducing friction therebetween. Similar friction bands are provided along the side edges of the locking strip to reduce friction drag.

These and other objects of the invention will become more apparent to those skilled in the art by reference to the following detailed description when viewed in light of the accompanying drawings wherein:

FIG. 1 is a side view in elevation of the printing apparatus of this invention;

FIG. 2 is a side view in elevation of the printing unit of this invention;

FIG. 3 is a perspective view of a portion of the printing apparatus of this invention;

FIG. 4 is an enlargement of the portion encircled in FIG. 2 in cross section;

FIG. 5 is a fragmentary cross-sectional view taken along lines 5-5 of FIG. 4; and

FIG. 6 is a fragmentary rear view of the ink distributing assembly of this invention.

Referring now to the drawings wherein like numerals indicate like parts, the numeral 10 generally indicates the printing apparatus supported at its ends by legs 12 and along its middle by vertical uprights 14. The printing apparatus generally comprises three levels of endless belt-type assemblies with platen belt assembly 16 at the lowest elevation, a locking strip assembly 18 at the intermediate elevation, and a second platen belt assembly or upper platen belt assembly 20 at the highest elevation. The assemblies 16, 18 and 20 are driven by motor 22 through endless drive belts, chains or the like 23. The upper and lower endless platens 16 and 20 both move in a clockwise direction such that their upper and lower runs respectively cooperate with the opposite runs of the counterclockwise driven endless locking strip 18 to thereby convey two separate webs of textile material 24 and 26 in opposite directions therebetween.

The lower platen assembly 16 comprises endless platen belt 28, consisting of a web of hard, flexible material such as rubber or plastic, disposed about rollers 30 and 32. The rollers 30 and 32 are rotatably secured in the legs 12 and are spaced far enough apart so that the run of the platen is longer than the run of the locking strip assembly 18. Between the rollers 30 and 32, the lower run of the platen 28 is supported by rollers 34 which are mounted on the uprights 14. lnwardly facing channels or side guide rails 36 are rigidly secured to the uprights 14 opposite the upper run of the platen 28 As best seen in FIG. 2, the side rails have a vertical web 38 provided with a flange or skirt 40 on its upper end and a flange 42 wider than said skirt on its lower end. This guide rail is connected to table 46 which table supports the run of the platen opposite the printing means.

The upper assembly 20 is identical to the lower assembly 16 except that is is positioned so that its lower run cooperates with the locking strip assembly 18. In other words, it is the mirror image of the lower assembly. The assembly includes a platen web 28' disposed around rollers 30' and 32, a pair of side rails 36' and a table 46. The intermediate rollers 50 rotatably mounted on the uprights 14 support the upper run of the web 28.

Heaters 31 and 38 can be disposed at each end of the printing apparatus as desired for purposes of drying the newly orinted webs 26 and 24 respectively. Each of the webs 24 and 26 are provided with takeup rolls 35 and 35' and feed rolls 37 and 37' respectively.

The locking strip assembly 18 is comprised generally of a parallel pair of endless locking strips 52 of resilient rubber-like material which passes over the opposite peripheral edges of end rollers 54 and 56 and a series of four twin drum printing units 58. The operation of the locking strip is fully described in my above-mentioned US. Pat. No. 3,468,247, issued Sept. 24, l969, Generally, with reference to FIG. 3, the upper and lower runs of the lock strip 52 are housed within the guide rails 36 and 36 and are urged against the vertical side edges of the respective platen belts 28 and 28' by bearing means which will be described more fully below. It is to be noted that the platen runs are longer than the locking strip runs and the webs 24 and 26 pass through a pair of conventional tensioning rollers 108 and are received on the respective platen webs 28 and 28. The textile webs 24 and 26 are wider than the platen belts and will therefore overhang the side edges somewhat. Consequently, since the locking strips normally tightly engage the vertical side edges of the respective platen runs, they will force the overlapping portion of the textile webs downwardly over the side edges of the respective platen belt tending to laterally stretch the material and thereby clamping the overlapped portion between the locking strip and the vertical side edges of the platen.

Rollers 104 and 104 are journalled on vertical axes at spaced points throughout the length of the side guide rails 36 and 36. An endless friction reducing band 106 passes around rollers mounted on vertical axes at each end of the series of roller bearings 104 such that the endless band substantially encompasses the bearings 104. The band 106 has an inner run tightly engaging the respective locking strip and moving with said locking strip, and an outer run adjacent said side guide rail 36. The friction reducing band is of a material such as stainless steel or of any other material which has a surface friction coefficient substantially less than that of the rubber locking strip and thereby minimizes frictional resistance between the locking belt and the hearing means. It is to be understood that as the respective platen moves through the apparatus, the locking strip is in substantially tight engagement with the side edges of the adjacent platen runs and moves in unison with Each drum printing unit is comprised of a pair of rotatable drums 62 over which passes a continuous printing screen 64. The screen 64 may be of nylon, dacron, silk, stainless steel or any other type material suitable for screen printing. The operation of the printing apparatus of this invention is not dependent on a particular screen material. The supporting mechanism renders the stencil screen 64 uniformly taut regardless of the material. Each screen 64 is suitably stenciled to provide the particular pattern desired. The stencils are attached to the rolls in a manner conventional to those skilled in the art. The rollers 62 of each printing unit are spaced apart and are rotatably secured in a framework generally indicated by the numeral 68 which comprises boxlike end supports 69 and 70 which are attached to the upper and lower side guide rails 36 and 36' respectively and extend around the tables 46 and 46' and the intermediate locking strip assembly 18. A crossbar 71 spans the'vertical portions of the supports 69 and 70 on each side and, along with the supports 69 and 70, rotatably supports the rollers 62.

An ink distributing assembly generally indicated by the numeral 74 is removably attached to the printing apparatus by means of T-bar support 76 which mates with fastening means 78. The support 76 is attached to a beam spanning the cross bars 71. The assembly comprises a housing 77 having a roller applicator 79 journaled therein and extending across and partially through an opening in the lower side of the housing 77. The roller applicator consists of a surface which is corrugated transversely of the length of the roller. As best seen in FIG. 4, closing the rear side wall of the housing is a squeegee 80 of a suitable semi-rigid material which is adapted to engage the screen stencil for purposes of removing excess ink which may be deposited by the roller applicator 79. Wheels 84 are journalled in brackets mounted on the front side of the housing and engage the stencil screen for purposes of stabilizing the ink distributing assembly. Ink from a reservoir or other suitable source which can be mounted on the printing apparatus or can be located at a remote point is fed to a manifold 86 which extends the length of the housing 77 which then extends transversely of the material to be printed. Ink from the manifold chamber 86 enters the cavity 88 defined by the housing 77 through tributary tubes 90.

Apivotally mounted doctor blade 92 extends the length of the roller applicator and includes a scalloped edge which engages and substantially mates with the corrugated surface of the roller applicator 79. The doctor blade 92 has an adjusting knob 94 by which te doctor blade may be pivoted toward and away from the roller to regulate the amount of ink transferred from the cavity 88 by the roller applicator 79 to the stencil screen surface 64. The corrugated surface'of the rollers provides a more even distribution of ink to the stencil screen. The surface by being corrugated has a tendency to better retain the ink that it has collected by its rotation past the cavity 88.

Since many printing processes use ink which dries rapidly upon exposure to the atmosphere, it is desirable to scrape the roller applicator during each application to remove excess ink not deposited on the stencil and cause it to recirculate and mix with fresh ink in the cavity 88. For this purpose, a second doctor blade 96 which is substantially identical to blade92 is pivotally mounted at the upper part of the cavity 88 in the housing 77. The doctor blade is pivotally adjustable by means of the knob 98 and removes excess ink not deposited on the stencil screen. The rotational movement of the roller applicator causes the removed ink to flow in the direction of the arrow over the doctor blade 96 into the flow of fresh ink in the cavity 88.

End plates 99 enclose each end of the housing and each has a resilient seal along its bottom edge maintaining the ink in the cavity substantially free from exposure to the atmosphere. The squeegee encloses one side, the ends plates seal each end, and the doctor blade 92 and roller 79 substantially close off the under side of the cavity. The roller applicator 79 is substan tially encompassed by the housing 77. This enclosed assembly localizes the ink and prevents ink from flowing to areas of the screen that cannot be scraped clean by the squeegee. It is to be understood that an identical ink distributing assembly 74' is used for the upper platen 28.

Each locking strip 52 is provided with toothed gear means in the form of a scalloped inwardly facing surface 53. Each roller 62 has toothed gear means in the form of a scalloped peripheral edge 63 about each end thereof. During operation of the device, the scalloped portion 53 of the driven locking strip 52 matches with the scalloped portions of the rollers 62 to thereby drive the rollersand, consequently, the stencil screen, at the same speed as the locking strips and the upper and lower platens 28 and 28'. Prior art devices relied upon friction contact between the rollers and the locking strips to drive the stencil screen. However, the provisions of the gearing arrangement as just described substantially insures absolute printing registration throughout the printing process.

In order to minimize the frictional contact between ducing bands is identical. Therefore, referring to the upper friction reducing band 110, best seen in FIG. 3,

its lower run extends between the table 46' and the lower run of the platen belt 28 and the upper run of the locking strip 52. Suitable lubricant is disposed between the surface and the friction reducing band to minimize frictional contact therebetween. The table may be ribbed longitudinally to further lessen frictional contact. It is to be understood that the friction reducing band is of a material which has a lower surface friction coefficient than that of the rubber-like platen. In opera tion, the friction reducing band travels with the platen because of the gripping action of the rubber-like platen material, and since there is little frictional resistance between the table and the friction reducing band, a minimum load is placed on the drive motor 22.

In operation, webs 24 and 26 of material to be printed pass in opposite directions in vertical spaced relationship through the printing apparatus 10 and are printed simultaneously by the stencil printing means 58 sandwiched between the upper and lower platen runs 16 and 20. Ink is distributed to the printing means by a substantially enclosed roller-applicator 79 having a corrugated surface. It is to be understood that the ink is supplied to the manifold 86 and cavity 88 from a tank or reservoir, not shown, and is under a certain amount of air pressure to cause it to flow to the cavity. The

pressure is not so great, however, as to cause the ink to be forced past the enclosing walls of the housing.

In a general manner, while there has been disclosed an effective and efficient embodiment of the invention, it should be well understood that the invention is not limited to such an embodiment as there might be changes made in the arrangement, disposition, and form of the parts without departing from the principle of the present invention as comprehended within the scope of the accompanying claims.

I claim:

1. ln an apparatus for continuously printing on a moving flexible material comprising a platen for receiving said material to be printed, said platen comprising a movable endless web having a top run and a bottom run, means for moving said material over said platen for movement therewith, printing means adjacent one of said runs of said platen for continuously printing said material supported by said platen, and a table supporting that portion of said one of said runs disposed opposite said printing means, the improvement comprising a movable endless friction reducing band of substantially planar sheet-like material having a surface friction coefficient less than that of said platen disposed within said endless platen and having a run extending between said platen run and said table and movable with said platen, thereby reducing friction between said platen and said table.

2. The apparatus of claim 1 and including a second endless platen vertically spaced from said first platen with said printing means being disposed therebetween, and a second supporting table and a second friction re-. ducing band for said second platen disposed in relation to said second platen as said first supporting table and first friction reducing band are disposed relative to said first platen.

3. In an apparatus for continuously printing on moving flexible material having lateral edge portions, comprising a platen for receiving said material to be printed having a lateral width less than that of said material, said platen comprising a movable endless web having lateral side portions and having a top run and a bottom run, means for moving said material into contact with and over said one of said runs of said platen, with said edge portions overlying said side portions of said one of said runs, printing means mounted adjacent said one of said platen runs for continuously printing said material as it passes between saidone of said runs of said platen and said printing means, said printing means including a pair of drums, an endless screen mounted for movement over said pair of drums, a table supporting that portion of said one of said runs adjacent said printing means, resilient strip means mounted adjacent the side portions of said one run of said platen and movable therewith for engaging and holding said edge portions against said side portions of said one of said runs, the improvement comprising gear means peripherally disposed about at least one end of each of said drums, and teeth means on said resilient strip means for driving interengagement with said gear means, whereby accurate registration between the printing means and said material is maintained.

4. In an apparatus for continuously printing on moving flexible material having lateral edge portions, comprising a platen for receiving said material to be printed having a lateral width less than that of said material,

said platen comprising a movable endless web having lateral side portions and having a top run and a bottom run, means for moving said material into contact with and over said one of said runs of said platen, with said edge portions overlying said side portions of said one of said runs, printing means mounted adjacent said one of said platen runs for continuously printing said material as it passes between said one of said runs of said platen and said printing means, a table supporting that portion of said one of said runs, resilient strip means mounted adjacent the side portions of said one run of said platen and movable therewith for engaging and holding said edge portions against said side portions of said one of said runs, bearing means secured to said table on each side of said one run of said platen for forcing said strip means toward said side portions to grip said edge portions of said material, said bearing means comprising rollers mounted on verticle axes, framework adjacent saidfstrip means for supporting said rollers, the improvement comprising an endless friction reducing band mounted around said rollers and extending substantially the length of said one run of said platen, said band having one face in contact with said strip means for movement therewith, and a second movable endless friction reducing band having a surface friction coefficient less than that of said platen disposed within said endless platen and having a run extending between said platen run and said table and movable with said platen thereby reducing friction between said platen and said table. 

1. In an apparatus for continuously printing on a moving flexible material comprising a platen for receiving said material to be printed, said platen comprising a movable endless web having a top run and a bottom run, means for moving said material over said platen for movement therewith, printing means adjacent one of said runs of said platen for continuously printing said material supported by said platen, and a table supporting that portion of said one of said runs disposed opposite said printing means, the improvement comprising a movable endless friction reducing band of substantially planar sheet-like material having a surface friction coefficient less than that of said Platen disposed within said endless platen and having a run extending between said platen run and said table and movable with said platen, thereby reducing friction between said platen and said table.
 2. The apparatus of claim 1 and including a second endless platen vertically spaced from said first platen with said printing means being disposed therebetween, and a second supporting table and a second friction reducing band for said second platen disposed in relation to said second platen as said first supporting table and first friction reducing band are disposed relative to said first platen.
 3. In an apparatus for continuously printing on moving flexible material having lateral edge portions, comprising a platen for receiving said material to be printed having a lateral width less than that of said material, said platen comprising a movable endless web having lateral side portions and having a top run and a bottom run, means for moving said material into contact with and over said one of said runs of said platen, with said edge portions overlying said side portions of said one of said runs, printing means mounted adjacent said one of said platen runs for continuously printing said material as it passes between said one of said runs of said platen and said printing means, said printing means including a pair of drums, an endless screen mounted for movement over said pair of drums, a table supporting that portion of said one of said runs adjacent said printing means, resilient strip means mounted adjacent the side portions of said one run of said platen and movable therewith for engaging and holding said edge portions against said side portions of said one of said runs, the improvement comprising gear means peripherally disposed about at least one end of each of said drums, and teeth means on said resilient strip means for driving interengagement with said gear means, whereby accurate registration between the printing means and said material is maintained.
 4. In an apparatus for continuously printing on moving flexible material having lateral edge portions, comprising a platen for receiving said material to be printed having a lateral width less than that of said material, said platen comprising a movable endless web having lateral side portions and having a top run and a bottom run, means for moving said material into contact with and over said one of said runs of said platen, with said edge portions overlying said side portions of said one of said runs, printing means mounted adjacent said one of said platen runs for continuously printing said material as it passes between said one of said runs of said platen and said printing means, a table supporting that portion of said one of said runs, resilient strip means mounted adjacent the side portions of said one run of said platen and movable therewith for engaging and holding said edge portions against said side portions of said one of said runs, bearing means secured to said table on each side of said one run of said platen for forcing said strip means toward said side portions to grip said edge portions of said material, said bearing means comprising rollers mounted on verticle axes, framework adjacent said strip means for supporting said rollers, the improvement comprising an endless friction reducing band mounted around said rollers and extending substantially the length of said one run of said platen, said band having one face in contact with said strip means for movement therewith, and a second movable endless friction reducing band having a surface friction coefficient less than that of said platen disposed within said endless platen and having a run extending between said platen run and said table and movable with said platen thereby reducing friction between said platen and said table. 